1. Field
The present disclosure relates generally to laser ultrasound testing and, in particular, to the laser ultrasound testing of composite structures. Still more particularly, the present disclosure relates to an apparatus, system, and method for using laser ultrasound testing to inspect regions of interest in areas to which access is limited.
2. Background
A laser ultrasound testing (UT) system is a nondestructive testing (NDT) system that may be used to test structures, such as composite structures, for undesired inconsistencies. A nondestructive testing system may also be referred to as a nondestructive inspection (NDI) system or a nondestructive evaluation (NDE) system.
Typically, a laser ultrasound testing system uses a laser beam to induce ultrasound within a composite structure. The laser beam may be a pulsed laser beam. The laser beam may be directed towards a location on a surface of a composite structure. When the laser beam encounters the surface of the composite structure, ultrasonic waves are formed in the composite structure.
The laser ultrasound testing system is capable of detecting these ultrasonic waves and using the detected ultrasonic waves to generate data about the composite structure. This data may then be used to identify information about the composite structure such as, for example, without limitation, a thickness of the composite structure, a material composition of the composite structure, an indication of whether any undesired inconsistencies are present on and/or in the composite structure, and/or other types of information.
In certain situations, a region of interest in a composite structure that is located in an area to which access is limited may need to be inspected. As one illustrative example, the bays formed by the spars of a horizontal stabilizer may be difficult to inspect. Some currently available traditional ultrasound systems may use ultrasonic arrays mounted to robotic arms or robotic crawlers that can be moved within the bays. However, these traditional ultrasound systems may be unable to handle variations in the shapes of the surfaces of these bays as well as desired. For example, these traditional ultrasound systems may be unable to handle the non-precise radii of curvature as well as desired.
Laser ultrasound testing systems may be able to handle variations in the shapes of surfaces. However, the size and/or weight of some currently available laser ultrasound testing systems may prevent these testing systems from being used in confined areas and/or other types of limited-access areas. For example, the types of laser ultrasound testing systems that may be needed to inspect a certain composite structure at the production level may require a large robotic cell. A robotic cell includes a robot, a controller, and/or other peripheral equipment. In some cases, the large robotic cell may be unable to move into and/or fit within certain areas.
Additionally, in some cases, higher power laser ultrasound testing systems require that testing be performed in areas or rooms that have shielding or some other type of protection for the eyes. Ensuring this type of protection may increase the expense of testing more than desired. The increased expense may reduce the feasibility of using these types of testing systems at the production level, or manufacturing level, of a composite structure.
Some lower power laser ultrasound testing systems may be used without requiring shielding. However, these types of testing systems may have a lower signal-to-noise ratio than desired. Consequently, the data generated using these types of testing systems may be less accurate and/or reliable than desired. Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues.